a.      Inner—The result set includes all the records in which the linked field value in both tables is an exact match. The Inner join is the standard type of join for most reports, and it is also commonly known as the Equal join.

b.     Left Outer—The result set includes all the records in which the linked field value in both tables is an exact match. It also includes a row for every record in the primary (left) table for which the linked field value has no match in the secondary (lookup) table. For example, if you would like your report to display all customers and the orders they have each placed—including the customers who have not placed any orders at all—you can use a Left Outer join between the Customer and Orders tables. As a result, you would see a row for every customer who has not placed any orders.

c.      Not Equal—The result set includes all records in which the linked field value in the primary table is not equal to the linked field value in the secondary (lookup) table. For example, if you needed to report on all orders that were not shipped on the same date that they were ordered, you could use the Not Equal join type to join the Order Date field in Orders table with the Ship Date field in the Order Details table.

d.     Full Outer—The result set includes all records in both of the linked tables—all records in which the linked field value in both tables is an exact match, in addition to a row for every record in the primary (left) table for which the linked field value has no match in the secondary (lookup) table, and a row for every record in the secondary (lookup, or right) table for which the linked field value has no match in the primary table. The Full Outer join is a bi-directional outer join, which essentially combines the characteristics of both the Left Outer and Right Outer joins into a single join type.